1. Field
The embodiments relate to a refrigerating apparatus, which improves freezing quality of stored articles, and a method of controlling the same.
2. Description of the Related Art
A refrigerating apparatus is an apparatus, in which the temperature of the inside of a sealed storage chamber is set to be lower than the external temperature, to store articles for a long time. The inside of the refrigerating apparatus is refrigerated by cold air generated by absorption of surrounding heat by a refrigerant when the refrigerant in a liquid state is evaporated in a refrigerating cycle, through which the refrigerant is circulated, and the stored articles are refrigerated through the refrigeration of the inside of the refrigerating apparatus.
In such a refrigerating apparatus, as shown in FIG. 1, an article stored in a storage chamber is refrigerated by the refrigerating cycle, through which the storage chamber is cooled to a temperature of −20° C. Here, a large difference between surface and center temperatures of the article stored in the storage chamber is generated, and freezing temperatures (i.e., freezing times) of the surface and the center of the stored article differ from each other. Thereby, ice crystals grow from the surface of the stored article to the center of the stored article. The closer to the center of the article, the more cells of the stored article are destroyed. Further, the temperature of the center of the article is raised again to the freezing point as phase change from moisture to ice at the center of the stored article occurs, and thus the time to lower the temperature of the center of the stored article is extended. Thereby, the stored article remains in a maximum ice crystal formation zone a1 for a long time a2, and thus large ice crystals or needle-shaped ice crystals are generated and the generated ice crystals destroy the cells of the stored article and lower the quality of the stored article. Accordingly, the stored article, such as animal and bird meat or fish, contains many drips after thawing, and loses much of its nutritional value, thus becoming unpleasant to taste.
In order to solve the above problem, the conventional refrigerating apparatus controls the temperature of the storage chamber using a refrigerating cycle using super-cooling, as shown in FIGS. 2A and 2B, to refrigerate a stored article. That is, cold air supplied to the storage chamber is set to a temperature of −5° C. for a designated time b2 such that the stored article is super-cooled at a designated temperature. When the designated time b2 has passed, the cold air supplied to the storage chamber is set to a temperature of −20° C. or less such that the super-cooling of the stored article is terminated, thereby starting simultaneous freezing of the surface and the center of the article, and thus reducing the size of ice crystals of the article. Since when the article is super-cooled, super-cooling may be terminated before the article reaches a designated temperature for the designated time b2, maintenance of the super-cooling of the article is difficult. Further, when the super-cooling of the article is terminated, the article remains in a maximum ice crystal formation zone b1 for a long time, and large ice crystals are formed in the article during this time, thus lowering the quality of the article. Moreover, when many articles to be stored are collected in the same container, the respective articles may be frozen at different points in time, and thus have different freezing qualities.